<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      .box {
        width: 200px;
        height: 200px;
        background-color: skyblue;
      }
    </style>
  </head>
  <body>
    <div class="box">123</div>
    <script>
      let div = document.querySelector('.box')
      div.style.width = '400px'
      div.style.height = '400px'
      div.style.backgroundColor = '#087'
      div.style.border = '2px solid blue'
      div.style.borderTop = '8px solid red'
    </script>
  </body>
</html>
